Ultra-thin heat pipe and manufacturing method thereof

ABSTRACT

An ultra-thin heat pipe and a manufacturing method thereof are provided. The ultra-thin heat pipe includes a flat pipe body and a powder-sintered portion. The flat pipe body has an internal wall, a first groove set and a second groove set, wherein the first groove set and the second groove set are disposed on the internal wall and spaced apart from each other, and each groove of the first groove set and the second groove set is extended along an extension direction of the flat pipe body. The powder-sintered portion is disposed within the flat pipe body and connects both the first groove set and the second groove set for forming at least one vapor channel with the internal wall.

This application claims the benefit of Taiwan application Serial No. 98120305, filed Jun. 17, 2009, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a heat pipe, and more particularly to an ultra-thin heat pipe and a manufacturing method thereof.

2. Description of the Related Art

Heat pipe has high thermo-conducting capacity. The liquid filled in the heat pipe is evaporated on the hot region of the heat pipe to form vapor. The vapor then moves along the vapor channel of the heat pipe towards the cold region at high speed. As the vapor arrives at the cold region, it is immediately condensed to form liquid, which can be affected by capillary attraction so as to move back to the hot region. By this working principle, heat can be rapidly transmitted from the hot region to the cold region.

However, electronic products at present are of small size and function at either high speed or efficiency, the solutions to heat-dissipating problem are in urgent need. Thus, a new heat pipe design with more excellent efficiency for satisfying the requirements of the electronic products is definitely needed.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an ultra-thin heat pipe with groove structure and great thermo-conducting capacity and a manufacturing method thereof for solving the inefficiency problem of the conventional heat pipe.

The invention achieves the above-identified object by providing an ultra-thin heat pipe, which includes a flat pipe body and a powder-sintered portion. The flat pipe body has an internal wall, a first groove set and a second groove set. The first groove set and the second groove set are disposed on the internal wall and spaced apart from each other, and each groove of the first groove set and the second groove set is extended along an extension direction of the flat pipe body. The powder-sintered portion is disposed within the flat pipe body and connects both the first groove set and the second groove set for forming at least one vapor channel with the internal wall.

The invention achieves the above-identified object by further providing a manufacturing method of ultra-thin heat pipe. The manufacturing method includes the steps of: providing a pipe body having a first groove set and a second groove set on an internal wall of the pipe body; cutting the pipe body for forming a cut pipe body with a first end and a second end opposite to the first end; sealing the first end of the cut pipe body; providing a plurality of to-be-sintered powders; filling in the cut pipe body with the to-be-sintered powders; sintering the powders within the cut pipe body for forming a powder-sintered portion connecting both the first groove set and the second groove set; filling in the cut pipe body with a working liquid; vacuuming the cut pipe body; and sealing the second end of the cut pipe body.

Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an ultra-thin heat pipe according to a preferred embodiment of the invention;

FIG. 2 is a diagram showing one cross-section of the ultra-thin heat pipe in FIG. 1;

FIGS. 3 and 4 are diagrams showing a powder-sintered portion having two sintered blocks;

FIG. 5 is a diagram showing the grooves located on the curved surfaces of the internal wall;

FIG. 6 is a diagram showing a flowchart of a manufacturing method of ultra-thin heat pipe according to a preferred embodiment of the invention;

FIG. 7A is a diagram showing a round pipe body;

FIG. 7B is a diagram showing an empty pipe material;

FIG. 7C is a diagram showing a mold pillar;

FIG. 7D is a diagram showing the cut of the pipe body;

FIG. 7E is a diagram showing a stick with non-curved surfaces;

FIG. 7F is a diagram showing the stick of FIG. 7E being inserted into the cut pipe body;

FIG. 7G is a diagram showing the to-be-sintered powders disposed within the cut pipe body of FIG. 7F;

FIG. 7H is a diagram showing a working liquid partially filled in the cut pipe body of FIG. 7G;

FIG. 8 and FIG. 9 are diagrams showing the round pipe body pressed by external force in different directions.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, FIG. 1 is a diagram showing an ultra-thin heat pipe according to a preferred embodiment of the invention, FIG. 2 is a diagram showing one cross-section of the ultra-thin heat pipe in FIG. 1. The ultra-thin heat pipe includes a flat pipe body 1 and a plurality of grooves 2. The grooves 2 are spaced with the same interval, disposed on the internal wall of the flat pipe body 1 and each extended along an extension direction of the flat pipe body 1, wherein the extension direction is, for example, the longitudinal direction of the flat pipe body 1, as shown in FIG. 1. The grooves 2 are divided into two groove sets 3 that are spaced apart from each other. The two groove sets 3 face to each other, wherein one of the groove sets 3 is disposed on the upper planar surface of the internal wall on the straight segment of the flat pipe body 1 while the other one is disposed on the lower planer surface of the internal wall. The flat pipe body 1 has two smooth segments 101 located between the two groove sets 3. The shape of the cross-section on each smooth segment 101 is, for example, semicircular, and the thickness on the smooth segments 101 of the flat pipe body 1 is smaller than that of the rest segments of the flat pipe body 1, such as the groove sets 3. Preferably, the material of the flat pipe body 1 is metal, such as copper, aluminum, stainless steel, titanium, nickel, etc., the thickness of the shell of the flat pipe body 1 is about 0.3 millimeter (mm), and the distance between any two adjacent grooves 2 is about 0.1 mm.

The ultra-thin heat pipe further includes a powder-sintered portion 4. The powder-sintered portion 4 is disposed within the flat pipe body 1 and connects both the upper groove set 3 and the lower groove set 3 for forming at least one vapor channel with the internal wall. In FIG. 2, the powder-sintered portion 4 includes a plurality of powders that are sintered together as a whole and connected both the upper and lower groove sets 3, forming two vapor channels 6 with the smooth segments 101. Preferably, the powders forming the powder-sintered portion 4 are sintered copper powders, aluminum powders, nickel powders, or nano-carbon powders. Besides, the diameter of at least one of the powders is preferably larger than the width of each groove 2.

Preferably, a plurality of burnable lines can be disposed in the powder-sintered portion 4. The burnable lines are removable by burning for increasing the number of holes within the powder-sintered portion 4. The material of the burnable lines can be nylon or cotton.

After sintered, the structure of the powder-sintered portion 4 contains a lot of small channels (holes) similar to capillary vessels that transport liquid by capillary attraction force. Because the size of each powder for sintering is larger than the width of each groove 2, the small channels (holes) within the powder-sintered portion 4 are able to receive a larger amount of liquid (condensed liquid), and the resistance for the liquid to flow in the powder-sintered portion 4 is reduced, enhancing the thermo-conducting efficiency of the heat pipe.

FIGS. 3 and 4 are diagrams showing a powder-sintered portion having two sintered blocks. The powder-sintered portion 4 is divided into two sintered blocks 41 and 42 that are spaced apart from each other. The sintered block 41 connects the upper groove set 3, and the sintered block 42 connects the lower groove set 3. In FIG. 3, the sintered block 41 aligns with the sintered block 42, and a gap 61 is located between the two sintered blocks 41 and 42 and connected the vapor channels 6. In FIG. 4, the sintered block 41 is disposed staggered with respect to the sintered block 42, and the two vapor channels 6 connect to each other directly.

The groove sets 3 are located on the planar surfaces of the internal wall of the flat pipe body 1, for example, however the invention is not limited thereto. FIG. 5 is a diagram showing the grooves located on the curved surfaces of the internal wall. As shown in FIG. 5, the groove sets 3 are disposed on the curved segments 103′ of the flat pipe body 1, and two smooth and straight segments 101′ are located between the curved segments 103′. Two sintered blocks 41′ and 42′ are disposed within the flat pipe body 1 in accordance with the groove sets 3 to form a single vapor channel 6′ with the upper and lower straight segments 101′.

As the ultra-thin heat pipe functions, the liquid filled in the flat pipe body 1 is evaporated on the hot region (not shown) of the heat pipe to form vapor. The vapor then moves along the vapor channels 6, 6′ of the heat pipe towards the cold region (not shown) at high speed. When the vapor arrives at the cold region, it is immediately condensed to form liquid. The condensed liquid is then affected by capillary attraction of the powder-sintered portion 4 and moves back to the hot region by the small channels (holes) within the powder-sintered portion 4. By this working principle along with the design of the powder-sintered portion 4, the vapor channels 6 and 6′, heat is rapidly transmitted from the hot region to the cold region with excellent efficiency.

The manufacture of the ultra-thin heat pipe disclosed above can be achieved by existing instruments. The groove sets can be formed on the internal wall of a pipe body first. Then, fill in the pipe body with to-be-sintered powders. After that, sinter the powders within the pipe body for forming a powder-sintered portion connecting the groove sets. Finally, flatten the pipe body for forming a flat pipe body. The manufacturing method of ultra-thin heat pipe is further elaborated in the following.

FIG. 6 is a diagram showing a flowchart of a manufacturing method of ultra-thin heat pipe according to a preferred embodiment of the invention. As shown in FIG. 6, the manufacturing method begins from step S01. In step S01, a pipe body having two groove sets on an internal wall of the pipe body is provided. Referring to FIG. 7A, a round pipe body 100 is shown. The grooves 2 of the groove sets 3 can be formed by different manners. Referring to FIG. 7B and FIG. 7C, an empty pipe material 10 and a mold pillar 12 are shown. The mold pillar 12 has two tooth sets 121, wherein an extension direction of each tooth 123 of the tooth sets 121 is identical with an extension direction of each groove 2 of the groove sets 3 (shown in FIG. 7A). The empty pipe material 10 is grooved by the mold pillar 12 to form the pipe body 100 with the two groove sets 3 (shown in FIG. 7A).

Next, as shown in step S02 of FIG. 6 and FIG. 7D, the pipe body 100 is cut for forming a cut pipe body 100′ with a first end 100 a′ and a second end 100 b′ opposite to the first end 100 a′.

Then, as shown in step S03 of FIG. 6 and FIG. 7D, the first end 100 a′ of the cut pipe body 100′ is sealed.

Next, as shown in step S04 of FIG. 6, a plurality of to-be-sintered powders are provided. Preferably, the diameter of the to-be-sintered powders is larger than the width of each groove of the groove sets, such that the powders will not be trapped within the grooves 2 (shown in FIG. 7A), maintaining the clearance of the grooves 2.

Then, as shown in step S05 of FIG. 6, FIG. 7E and FIG. 7F, a stick 14 is inserted into the cut pipe body 100′, wherein the stick 14 has two non-curved surfaces 14 a corresponding to the two groove sets 3.

Next, as shown in step S06 and FIG. 7G, fill in the cut pipe body 100′ with to-be-sintered powders. As the stick 14 occupies partial space within the cut pipe body 100′, the powders can be maintained at the predetermined locations corresponding to the two groove sets 3.

Then, as shown in step S07 and FIG. 7G, the powders within the cut pipe body 100′ are sintered for forming a powder-sintered portion 4 having two sintered blocks 41 and 42 connecting the two groove sets.

Next, as shown in step S08, the stick 14 is removed out of the cut pipe body 100′.

Then, as shown in step S09 and FIG. 7H, the cut pipe body 100′ is partially filled in with a working liquid 16, such as water, which is used for conducting heat by evaporating and condensing.

Next, as shown in step S10 and FIG. 7H, the cut pipe body 100′ is vacuumed. That is, the air within the cut pipe body 100′ is withdrawn out of the cut pipe body 100′.

Then, as shown in step S11, the second end 100 b′ of the cut pipe body 100′ (shown in FIG. 7D) is sealed for forming a round pipe body.

Next, as shown in step S12, the cut pipe body 100′ is flattened for forming a flat pipe body.

FIG. 8 and FIG. 9 are diagrams showing the round pipe body 100′ pressed by external force in different directions. As shown in FIG. 8, the external force is applied to the round pipe body 100′ on the locations in accordance with the groove sets 3 so as to deform the round pipe body 100′ as well as reduce the distance between the two groove sets 3. The round pipe body 100′ can be pressed till the two sintered blocks 41 and 42 in contact with each other to form a single powder-sintered portion 4, as shown in FIG. 2. Or the sintered blocks 41 and 42 can be kept apart, as shown in FIG. 3 or FIG. 4.

As shown in FIG. 9, the external force is applied to the round pipe body 100′ on the locations in accordance with the smooth segments 101. After flattened the round pipe body 100′, a flat pipe body similar to the flat pipe body 1 of FIG. 5 is thus produced.

While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures. 

1. An ultra-thin heat pipe, comprising: a flat pipe body having an internal wall, a first groove set and a second groove set, wherein the first groove set and the second groove set are disposed on the internal wall and spaced apart from each other, and each groove of the first groove set and the second groove set is extended along an extension direction of the flat pipe body; and a powder-sintered portion disposed within the flat pipe body, connecting both the first groove set and the second groove set for forming at least one vapor channel with the internal wall.
 2. The heat pipe according to claim 1, wherein the segments of the internal wall between the first groove set and the second groove set are smooth.
 3. The heat pipe according to claim 2, wherein the shape of the cross-section of the flat pipe body on at least one of the segments is semicircular.
 4. The heat pipe according to claim 1, wherein the first groove set is disposed on one planar surface of the internal wall.
 5. The heat pipe according to claim 1, wherein the first groove set is disposed on one curved surface of the internal wall.
 6. The heat pipe according to claim 1, wherein the grooves of the first groove set are spaced with the same interval.
 7. The heat pipe according to claim 1, wherein the powder-sintered portion comprises a plurality of powders sintered together, and the diameter of at least one of the powders is larger than the width of each groove.
 8. The heat pipe according to claim 1, wherein the powder-sintered portion comprises a plurality of powders sintered together and divided into a first sintered block and a second sintered block, the first sintered block connects the first groove set, and the second sintered block connects the second groove set.
 9. The heat pipe according to claim 8, wherein the first sintered block and the second sintered block are spaced apart from each other.
 10. The heat pipe according to claim 8, wherein the first sintered block aligns with the second sintered block.
 11. The heat pipe according to claim 8, wherein the first sintered block is disposed staggered with respect to the second sintered block.
 12. The heat pipe according to claim 1, wherein the thickness of the shell of the flat pipe body is about 0.3 millimeter (mm).
 13. The heat pipe according to claim 1, wherein the distance between any two adjacent grooves is less than 0.1 mm.
 14. The heat pipe according to claim 1, further comprising: a plurality of burnable lines disposed in the powder-sintered portion, wherein the burnable lines are removable by burning for increasing the number of holes of the powder-sintered portion.
 15. The heat pipe according to claim 14, wherein the material of the burnable lines is nylon or cotton.
 16. The heat pipe according to claim 1, further comprising: a working liquid partially filled in the flat pipe body.
 17. A manufacturing method of ultra-thin heat pipe, comprising: providing a pipe body having a first groove set and a second groove set on an internal wall of the pipe body; cutting the pipe body for forming a cut pipe body with a first end and a second end opposite to the first end; sealing the first end of the cut pipe body; providing a plurality of to-be-sintered powders; filling in the cut pipe body with the to-be-sintered powders; sintering the powders within the cut pipe body for forming a powder-sintered portion connecting both the first groove set and the second groove set; filling in the cut pipe body with a working liquid; vacuuming the cut pipe body; and sealing the second end of the cut pipe body.
 18. The method according to claim 17, further comprising: flattening the cut pipe body for forming a flat pipe body.
 19. The method according to claim 17, before the step of filling in the to-be-sintered powders, further comprising: inserting a stick into the cut pipe body, wherein the stick has two non-curved surfaces corresponding to the first groove set and a second groove set.
 20. The method according to claim 19, after the step of sintering the powders, further comprising: removing the stick out of the cut pipe body.
 21. The method according to claim 17, wherein the step of providing the pipe body comprises: providing an empty pipe material; and using a mold pillar having a first tooth set and a second tooth set to groove the empty pipe material for forming the first groove set and the second groove set.
 22. The method according to claim 21, wherein an extension direction of each tooth of the first tooth set and the second tooth set is identical with an extension direction of each groove of the first groove set and the second groove set. 